1. Field of the Invention
The present invention relates to a wireless sensor which performs sensing process and routing process and a method of controlling the activation of it.
2. Description of the Related Art
A sensor network is constructed from a number of wireless sensors which perform sensing process and routing process. With the sensor network, each of the wireless sensors individually carries out sensing process to obtain information and sends the information to the others. The information is collected by a server, thereby allowing complex situations or environments to be grasped.
With a sensor network described in “D. Tian and N D. Georganas. A Coverage Preserving Node Scheduling Scheme for Large Wireless Sensor Networks. Wireless Sensor Networks and Applications. pp. 32-41 (2002)”, each wireless sensor notifies the other sensors of its sensing area. Each wireless sensor makes a decision of whether or not its sensing area overlaps with that of any of the other sensors and, in the presence of an overlap, turns off its power source. With the sensor network described in the related art, therefore, if the sensing areas of wireless sensors overlap each other, the overall power consumption of the network can be reduced.
With the sensor network described in the related art, if the sensing areas of wireless sensors do not overlap each other, the advantage of reducing power consumption cannot be achieved. That is, since most of the wireless sensors the sensing areas of which do not overlap with each other are in the steady activated state, a great reduction in the overall power consumption of the network cannot be expected.